The present invention relates to a micromirror array lens with free surface. More particularly, this invention relates to a micromirror array lens with free surface that enables high performance with compactness.
Spherical lens cannot converge parallel rays into one point. Therefore, many lenses are combined to correct it. In those cases, since many lenses are assembled, there is limitation in achieving high performance of a large-aperture lens with compactness.
On the other hand, if an aspherical lens with desired free surface which can gather rays at one point is used, it can converge parallel rays into one point with a single lens. It can reduce volume and weight of optical system. High optical performance is also possible.
For this reason, an aspherical lens has been used for beam projector, projection TV, CD-ROM pickup, DVD player, laser printer, laser scanning unit, etc.
But, it is difficult to make an aspherical lens with actually required complicated aspheric surface of accuracy less than 0.1 μm with existing machine performance. In addition, it is difficult to measure the misbehavior of the lens produced with less than 0.1 μm accuracy. On the other hand, micromirror array lens with free surface can form aspherical lens with accuracy less than 0.1 μm.